In the chemical industry, measuring the flow of chemical substances is highly hazardous. Due to varying parameters such as corrosion, viscosity, temperature, and pressure, flow meters must be selected. Electromagnetic flow meters, ultrasonic flow meters, and turbine flow meters are commonly used to measure the flow of media in chemical applications.
This article introduces the selection and application of flow meters within the chemical industry in detail.
What is a Chemical Flow Meter?
A chemical flow meter is a device used to measure the flow of chemicals. They use many technologies, such as ultrasonic, magnetic, or thermal principles, to measure flow. Chemical flow meters can measure the flow of chemicals in extreme environments, such as corrosive substances, high viscosities, high temperatures, and high pressures. They are commonly used in the chemical industry for flow measurement and monitoring.
Challenges in Chemical Flow Measurement
Chemical media have very complex characteristics. Therefore, flow monitoring in the chemical industry faces many challenges:
Complex Media:
Corrosive (e.g., strong acids, alkalis). Flammable/explosive and multiphase mixtures. High viscosity (e.g., polymer solutions).
Harsh Environments:
High temperatures media (>200°C), high-pressure media (>10MPa), and strong vibration conditions.
Accuracy and Response Speed:
Some reactions necessitate real-time flow adjustment (e.g., catalyst injection). It demands millisecond-level response capabilities.
Maintenance Difficulties:
Certain process pipelines cannot be shut down for maintenance. It requires low-maintenance or remote monitoring solutions.
Safety and Environmental Pressure:
Leaks or control failures may cause safety incidents and environmental pollution. Solutions must balance precision and reliability.
Sino-Inst Featured Chemical Flow Meter
Working Principles of Various Chemical Flow Meters:
Chemical flowmeters can be categorized into different types based on their operating principles.
Differential pressure flow meter working principle: The pressure differential generated when a medium flows through a throttling device has a constant relationship with the flow rate. It can be used to measure the flow of most liquids, gases, and steam. However, in the chemical industry, the impact of clogging on accuracy must be considered.
Gear flow meter working principle: When the measured liquid enters the flowmeter through the pipeline, the pressure difference generated at the inlet and outlet drives a pair of gears to rotate continuously, continuously transporting the liquid measured by the crescent-shaped cavity to the outlet. The product of the number of revolutions of the elliptical gear and four times the displacement each time is the total flow rate of the measured liquid. Gear flow meters are commonly used to measure high-viscosity media such as glue and oil.
Target flow meters measure flow rate using the pressure differential generated by fluid flow in a pipe.
Generally, they consist of an annular target and a pair of differential pressure sensors. When the fluid flows through the annular target, it encounters resistance and changes direction, generating a pressure differential. The sensor measures this pressure differential signal and converts it into an electrical signal. This signal is then processed by a processing unit to calculate and output the flow rate value. Target flow meters excel in demanding flow measurement conditions such as high viscosity, contaminated media, substances prone to clogging, extreme temperatures, and severe corrosion.
A positive displacement flow meter is abbreviated as a PD flow meter. It employs mechanical measuring elements to continuously divide the fluid into discrete known-volume segments. Total fluid volume is measured by counting the number of times the measuring chamber sequentially fills and discharges these volume segments. It is suitable for high-temperature, low-temperature, high-pressure, low-pressure, and viscous media.
Turbine flow meters represent a primary type among velocity-type flow meters. They employ a multi-bladed turbine to sense the average fluid velocity, thereby deriving flow rate or total volume. Typically consisting of a sensor and display unit, they may also be integrated into a single unit. Turbine flow meters are commonly used to measure: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas, and cryogenic fluids.
Electromagnetic flow meters are instruments based on Faraday’s law of electromagnetic induction. It is designed to measure conductive liquids. They measure various corrosive liquids. such as acids, alkalis, and salts. Flammable and explosive media. Industrial wastewater, pulp, slurry, etc. Electromagnetic flow meters cannot be used to measure gases, vapors, or liquids containing significant gas content. They are unsuitable for measuring liquids with very low conductivity. And it cannot handle high-temperature or high-pressure fluids.
Vortex flow meters incorporate a non-streamlined vortex generator into the fluid flow. As the fluid passes around the generator, it alternately separates and releases two rows of regularly spaced, interlaced vortices. Vortex flow meters are suitable for measuring liquids, general gases, and steam.
Ultrasonic flow meters measure flow rate by detecting the time difference between the transmission and reflection of ultrasonic pulses through the fluid. They operate non-contact, incur no pressure loss, and can measure non-conductive liquids.
Coriolis mass flow meters measure medium flow based on the Coriolis force principle. They represent the most accurate category among all flow meters. Coriolis mass flow meters directly measure fluid mass flow. It is unaffected by variations in temperature, pressure, or density.
Chemical Flow Meters Applications
Chemical Raw Material Metering and Batching Systems
In fine chemical, coating, and adhesive production, chemical flow meters are used to precisely measure the addition of raw materials, such as resins, solvents, and curing agents, ensuring formulation consistency.
Acid and Alkali Solution Transfer and Dosage Control
Chemical Flow Meters are employed for transferring and metering corrosive liquids like concentrated sulfuric acid, sodium hydroxide, and hydrochloric acid in wastewater treatment and neutralization reactions. We recommend the PTFE-lined or Hastelloy materials to prevent corrosion.
Solvent and Intermediate Transfer
In the pharmaceuticals, fragrances, and dyes industries, chemical flow meters enable precise transfer of organic solvents like toluene, ethanol, and acetone.
High-Viscosity Material Filling
On filling lines for lubricants, silicone oils, polymer melts, etc., chemical flow meters provide stable measurement of high-viscosity fluids. Avoid errors caused by viscosity in traditional flow meters.
Flow Monitoring in CIP Systems
In processes requiring frequent cleaning, chemical flow meters ensure the operation of advanced CIP systems. The chemical flow meters measure current volumetric flow rates and total consumption across various CIP pipelines. It enables workers to adjust CIP formulation ratios accordingly.
How to Choose the Perfect Chemical Flow Meter?
When you select a perfect chemical flow meter, consider the following parameters:
- Medium Properties: Density, viscosity, pressure, temperature, and chemical characteristics all impact the flow meter’s performance and service life.
- Measurement Method: Options include thermal, vibrating, differential pressure, and others.
- Flow Range: Determine the flow range based on actual operation conditions. Select a flow meter with a suitable measurement range.
- Accuracy: Determine the required precision class based on specific operation needs. Different industrial applications have varying precision requirements.
- Environmental: Confirm the operating temperature, pressure, corrosiveness, humidity, and other parameters.
- Pipe Compatibility: When measuring corrosive media such as acids and alkalis, ensure the pipe material is compatible with the flow meter. We propose selecting models with corrosion-resistant contact parts or linings.
Sino-Inst has many years of flow measurement experience. We propose the following flow meters for a specific medium:
Turbid liquids (e.g., sewage, pulp, slurry)
Optional: Mass flow meter. Doppler ultrasonic flow meter. Electromagnetic flow meter.
Note: Electromagnetic flow meters require extremely low air/bubble content in liquids.
Petroleum, diesel, and other oil-based media
Optional: Mass flow meters. oval gear flow meters. turbine flow meters. metal rotor flow meters.
High-concentration media containing solid particles, such as slurries and two-phase liquids
Optional: Mass flow meters. electromagnetic flow meters. For high-viscosity media, target flow meters may be selected.
High-flow media like tap water
Optional: Mass flowmeter, electromagnetic flowmeter, vortex flowmeter, orifice plate flowmeter, various Pitot tube flowmeters, etc.
Gaseous medium
Optional: Mass flowmeter, thermal gas mass flowmeter (excluding water vapor), vortex flowmeter, gas turbine flowmeter, orifice plate flowmeter, various Pitot tube flowmeters, etc.
Low-conductivity media (e.g., purified water, deionized water)
Optional: Mass flow meter. vortex flow meter. turbine flow meter. ultrasonic flow meter, etc.
Highly corrosive media (e.g., acids, alkalis)
Optional: Electromagnetic flow meter with acid/alkali-resistant lining & electrodes. mass flow meter with special materials. clamp-on ultrasonic flowmeter.
When you select a suitable flow meter, please comprehensively consider the above factors. Carefully compare the applicable ranges of different flow meter types to choose the perfect one for your application. We also recommend consulting professionals before making a decision. Sino-Inst will recommend the most appropriate measurement solution for you.
Chemical Flow Meters and Calibration
The production environment in the chemical industry is highly complex. Therefore, flow meter calibration is critical. Failure to calibrate flow meters regularly may lead to errors that could cause serious accidents. Based on Sino-Inst’s many years of measurement experience, we offer several flow meter calibration methods for your reference:
Comparative Calibration:
Comparative calibration involves comparing the device under test with a flowmeter of known accuracy. This method is suitable for scenarios where multiple flowmeters operate simultaneously. By comparing the measurement ways from multiple flow meters, adjustments can be made as needed. This method has the ability to quickly confirm flow meter errors and apply corresponding corrections.
Static Calibration:
It uses a standard fluid to test the precision of a flow meter. This method is simple and direct. It is suitable for certain volumetric flow meters and mass flow meters. Static calibration mainly requires a laboratory environment. The laboratory ensures stable and controllable fluid flow.
Dynamic Calibration:
It typically employs a standard flow source. Calibration occurs under the flowmeter’s normal operating conditions. This method simulates the flow meter’s actual operation environment. Provide a more accurate reflection of its real-world performance.
Dynamic calibration is suitable for most online flow meters, such as turbine flow meters and electromagnetic flowmeters. It reflects the flow meter’s actual performance in production settings.
Standard Liquid Calibration:
Standard Liquid Calibration is usually for flow meters requiring high-precision flow measurement. This technique employs a standard liquid with known density and viscosity. The flow meter is calibrated by measuring the flow of the standard liquid. Standard Liquid Calibration is typically used in chemical processing and pharmaceutical manufacturing. These industries demand extremely high precision and stability.
What is the best flow meter for sludge?
Electromagnetic flow meters are suitable for sludge flow measurement. Sludge flow meters primarily measure the volumetric flow of conductive liquids like sludge and slurries. Electromagnetic flow meters are a common type of sludge flow meter.
How to read a flow meter?
Most flow meters feature built-in displays that show real-time instantaneous flow and cumulative flow data. Flow readings can be obtained directly from these displays.
For meters without displays, the flow meter must be connected to a secondary instrument. The flow meter converts the relevant flow value into an electronic signal and transmits it to the secondary instrument for reading.
How to Calculate Flow Rate?
Pipe Water Flow Rate:
Common pipe water flow measurement devices are Doppler flow meters, vortex flow meters, and electromagnetic flow meters.
The water flow rate formula is: Q = A * V
Where: A is the pipe cross-sectional area. V is water flow velocity. Q is the water flow rate.
Read more: Flow Rate and Pressure Relationship Formula
Calculating Channel Water Flow:
Common channel water flow measurement devices include Doppler current meters and the float method. Currently, most channels utilize Doppler flow meters. As non-contact flow measurement devices, they offer high accuracy and simple installation. They only need to be mounted on brackets fixed to the channel bottom.
In short, chemical flow meters play a crucial role in flow measurement during chemical production processes. If you need to measure chemical flow rates but are unsure how to select the appropriate flow meter, I recommend contacting us immediately.
Sino-Inst has specialized in flow measurement for years. We possess successful flow measurement experience across diverse industries. We supply a comprehensive range of flow meters, including electromagnetic flow meters, ultrasonic flow meters, and turbine flow meters, all characterized by excellent quality and extensive product types. Choosing us ensures a seamless purchasing.
